Thanks Aussie,

Something worth noting with BYCOL & BYROW is that when using functions such as:
SUM, AVERAGE, MEDIAN, COUNT, COUNTA, MAX, MIN, PRODUCT, ARRAYTOTEXT, CONCAT etc..

You don't need to use LAMBDA.

For example:
=BYROW(A2:C4,LAMBDA(row,SUM(row)))

Could be written as:
=BYROW(A2:C4,SUM)

Same with:
=BYCOL(A2:C4, LAMBDA(col, AVERAGE(col)))

Could be:
=BYCOL(A2:C4,AVERAGE)